This invention relates to a drawing paper cutting system for automatic drawing machines using continuous roll type drawing paper.
In a conventional drawing paper cutting method for automatic drawing machines using continuous roll type drawing paper, the drawing paper is cut by actuating a cutter in accordance with a cutting instruction from a host computer. In this method, it is necessary to provide cables for transmitting instructions for actuating the cutter, and interfaces on the side of both the cutter and host computer. Accordingly, different interfaces are required for different types of host computers. The host computer and the automatic drawing machine and paper cutting unit are operated synchronously and consistently. Therefore, the drawing paper must be cut during a drawing operation, and cannot be cut afterward.
The cutting unit for this type of drawing machine using continuous roll type drawing paper consists solely of a Y-axis cutter means, which has rotary and fixed blades disposed in opposition to each other on both sides of the drawing paper and adapted to cut the drawing paper continuously in the Y-axis direction which is at substantially right angles to the direction in which the drawing paper is fed, by bringing an edge of the fixed blade into contact with that of the rotary blade. The roll paper is thus cut at regular intervals only in the paper-feeding direction. It is needless to say that this cutting unit is incapable of cutting the drawing paper in the X-axis direction which is parallel to the paper-feeding direction. therefore, in this cutting unit, the drawing paper is cut to only a predetermined size. Hence, even when an intermediate-sized or large-sized automatic drawing machine having a cutting unit for, for example, A1-sized drawing paper is used with a view to outputting an A4-sized drawing therefrom, the drawing paper is cut to the A1-size, so that the area of the effective region of the cut drawing paper is 1/3 of the total area thereof with the remaining 2/3 of the total area thereof occupied by a blank region. Consequently, if the drawing paper is used in this manner, much more than the required quantity of drawing paper is consumed, i.e., a large amount of drawing paper is wasted. To store such an outputted drawing according to its size for the purpose of using the drawing as an original, it is necessary that the blank portion thereof be cut off so as to set the size of the drawing to a desired size. This causes a great decrease in the operating efficiency of a high-output drawing machine.